Ink



Patented Oct. 11, 1927.

UNITED STATES v 1,645,117 PATENT OFFICE.

HERMANN SCHLADEBACH, OF DESSAU IN ANHAL'I, AND HERBERT HKHLE, OF DESSAU- ZIEBIGK IN ANHALT, GERMANY, ASSIGNORS TO I.-G. FABBENINDUSTRIE AKTIEN- INK.

No Drawing. Application filed January S 1926, Serial No. 80,068, and in Germany January 8, 1925.

Besides the known tannin-iron inks and logwood-chrome inks dyestuff inks have been made in wide variety. For instance, solutions of cosine have been used as red inks, solutions of methyl violet as violet inks, and solutions of acid green as green inks. Evenblack inks have been made-from coaltar dyes, chiefly from solutions of nigrosine or black acid azo dyes. Substantive cotton dyes have been similarly used.

Such dyes have the disadvantage that the writing Iproduced with them is capable of being w olly or in part washed rom the paper by water. In the case of basic and acid dyes for wool, this is only to be expected since they are soluble in water and do not form an com ound with the paper or otherwise su er a c ange on the paper. However, even substantive dyes which have an affinity for celluloseare not likely to prove of muc *use as water-proof inks, even though in dyeing cotton they yield water-fast dyeings, because in writing on paper the conditions which revail are wholly different from those 0 the dyeing process.

.In order to make writing inks fast to water, shellac dissolved in borax solution has been added to dye inks. Such dye solutions are not, however, easily flowing inks which can be used-for writing with a pen but India inks which are especially useful for drawing lines. I

- By the present invention it is possibleto make dyeings which are fast to water and are useful for writing from suitable azodyes which dye cotton directly b adding to the dye solution a free alkali, for instance potash lye or soda lye. The degree of fast ness to water which is achieved and the speed with which the fastness to water is develo ed after the writing is dry differ with the several dyes. In many cases the writing is fast even within an hour after it is dry; in other cases the same result occurs of astness to water also depends on the kind of size which is present in the paper used. The presence of resin size causes a much more rapid development of fastness to water than ge atine slze. The development of the water proof character of the writing can be greatly accelerated by adding to the dye so lution in addition to' the alkali a small amount of formaldehyde. Instead of formaldehyde an agent maybe used which and the solution is made u onl after days. The speed of development yields formaldehyde. Dyes which contain free aminoor hydroxyl groups yield inks capable of producing writing which rapidly becomes fast to water without addition of alkali when formaldehyde is present in the dye solution. Certain compounds, such as glycerine, aleohol,.phenol, tannin, may be added to the inks, which should be free from precipitates and should contain as small a proportion of salt as possible, in order to vary the duration of drying, the freedom of flow and other properties.

The following examples illustratethe invention without limiting it:

Example 1.20 grams of a dye of a general formula: I

zo-pam-diamlne-azo-meta- I diamlue Aminonaphtholsulphomo acid azopara-diamlna-azo-metadlamlne are dissolved in 950 com. of distilled water. After cooling and filtering 50 ccm. of 2%- sodium hydroxide solution are added and the whole is made u to 1000 ccm. Writing produced with these mks islfast, even to boiling water.

Ewmnple 2.About 19 rams of a dye having a general formula g1ven in Exam le 1 are dissolved in 940 com. of boiling 'stilled water. After cooling and filtering 10 ccm. of a solution of formaldehyde of 30 per cent strength and 50 com. of 2n-sodium hydroxide solution are added and the whole made up to 1000 ccm. Writing roduced with these inks is water-fast ina s ort time and also is very soon fast to dilute alkali.

Ewample 3.About 12 grams of a dye of the general formula given in Example 1 containing some sodium carbonate used while preparing the dye are dissolved in 950 ccm. of boiling distilled water. After cooling and filtering 50 ccm. of a formaldehyde solution of 30 per cent strength are added to 1000 ccm. Writing produced with this1nk is complete- 100 ly fastzto water after a short time.

Ewmm le 4.A mixture of 8.2 grams of a dye of t e general formula:

, onaphtholsulphonlc acid-ozometa-diamlne Dlamlnodiphouyhmhi zo-amlnonaphtholsulphonlc aeid me o,

2.2 grams of a dye of the formula: 1.4-diaminoarylsulphomc acid-azo-l-aminonaphthalene-azo-aminohydroxynaphthalene ul- 'aminophenoletherazo aminohydroxynaphthalene sulphonic acid (ammonium salt) containing some alkaline salt used while preparing the dye are dissolved in 950 com. of boiling distilled water. After cooling and filtering 50 com. of a formaldehyde solution of 30 per cent strength are added. The writing produced with this ink is fast to water and to dilute alkali immediately after drying. i a

n the appended claims the term azo-d'ye which dyes cotton directly is used to include those azo-dyes which are capable of dyeing cellulose fibers without the aid of a mordant such as tannin and metal salt mordants. In the dyeing industry the dyes of this class are designated substantive dyes.

What we claim is,-

I. An" ink comprising a solution of an azo-dye which dyes cotton directly and a free alkaline agent in a quantity sufiicient to render writings produced with the ink fast to water.

2. An ink comprising a solution of an azo-(lye which dyes cotton directly, formaldehyde, and a free alkaline agent in a newtity sufficient to render writings pro need with the ink fast to water.

3. An ink comprising an aqueous solution of an azo-dye which dyes cotton directly and a free caustic alkali in a quantity sufficient to render writings produced with the ink fast to water.

4. An ink comprising an aqueous solution of an azo-d e which dyes cotton directly, formaldehy e, and a free caustic alkali in a guantity sufiicient to render writings prouced with the ink fast to water.

In testimony whereof we affix our signatures.

HERMANN SQHLADEBACH. HERBERT HAHLE. 

